In the recording of electon energy loss elemental maps, the background spectrum at each pixel of the image must be subtracted from the measured signal above a characteristic core edge. Previously, other laboratories involved in this work have used only one channel for the background estimation. However since the shape of the background is known to change as a function of sample mass thickness, the resulting images have been liable to contain artifacts. New software has therefore been written to test the effects of mass thickness on the energy loss images, recorded with the Hitachi 200 KeV analytical electron microscope. It is possible to predict when artifacts will occur and to correct for them, and in doing so improve the statistics in the elemental maps.